There is a desire to improve accuracy of projectiles by incorporating active control throughout the flight. Often in order to keep both package volume and cost to a minimum these precision rounds are controlled remotely. This is particularly true for small projectiles including bullets. A major difficulty arises in that the directing source is not in sync with the rotation of the spinning projectile. Commands to the spinning projectile are generally given in an inertial space reference and the round itself must maintain knowledge of its launch accelerations followed by the rapid spin rate required to maintain stability of the round through flight, on-board gyroscopes become cost prohibitive.
Polarized signals have been proposed for use in determining round orientation relative to a transmitted source. These approaches detect a polarized return from the round to determine when to issue fire commands from the ground station. This system is complicated by the need for a means of generating a return signal in order to coordinate the command from the ground.
An alternative approach has been proposed wherein a pair of polarized signals are transmitted and the round itself determines roll attitude. Such methods concentrate on the task of providing the round a means of determining absolute orientation in inertial space such that commands communicated in this reference system would be properly executed.
What is needed, therefore, are techniques for cost effective flight remote control of spinning projectiles.